Trunk telephone office without three cords



Dec. 11, 1951 HENQUET ETAL 2,577,759

TRUNK TELEPHONE OFFICE WITHOUT THREE CORDS I Filed July 23, 1947 2SHEETS-SHEET l LJ v I 4, CJ [l R A [I LOT cc FIG. I.

g L J l I 43 i i 6 |2 I09 7 8 3 4 2 FIG. 2.

l mmvrons- ANDRE JEAN HENQUET FIG 3 BY MARCEL ROGER MAUGE ATTORNEY Dec.11, 195] HENQUET ETAL 2,577,759

TRUNK TELEPHONE OFFICE WITHOUT THREE CORDS Filed July 25. 1947 2SHEETSSHEET 2 i A INVENTORS a q- ANDRE JEAN HENQUET I a o{|- TH w MARCELROGER MAUGE i LE B N |H- m I [a -o v I a 5' ATTORNEY Patented Dec. 111951 IUNrr'ED STATES The: present invention relates to trunk telephoneexchanges that do not employ the plug ended or triple-cords generallyused for interconnecting 1st class circuits. These triple-cords, whichmake it possible to extend the four wires of 1st class circuits inorderzto efie'ct'the linkin of tWo conversationchannels, sufierfromserious drawbacks, particularly "that of crowding the equipment of thetoll boards and complicating the 'tasks :of the operators.

aJIhe i-presentinvention consequently aims at providing trunk telephoneexchange arrangements that make it possible to handle the trafficbymeans=of the usual two plug ended or doubl'e-cords, irrespective of theconnections to be established. l

. According to certain features of the invention, this purposeisattainedbythe use of a diversion circuit which; is permanentlyprovided in the ex;- changes equipment and which is automaticallybrought into play every time it is necessary-.lto link two *1st classconversation channels,ithe manual operations remain the same assforlower. class circuits,. in other words, plugging in by theoperatorwithxher double-cord. The exchanges equipment is however:arranged' so asv to provide normal service for .lower class circuitconnec-l tions. 7,. Fig. 1 shows the generalschemexforiconnectingtogether two 1st class circuits. l.

Fig. Z-shows the portion of .anincoming'or outgoing 1st class circuitthat is necessary for describing the operation of trunkexchanges-employing features of the invention.

- Simila-rly, Fig. 3 shows a portion'of the-double: cord at theoperators position, 7 Fig. 4 shows an example of a 4-wire link circuitfor linking together 1st class circuits, accordingtoieatures of theinvention. V M

H As shownin Fig.1, the general scheme for 1st class circuit connectionscomprises, according to features of the invention, a diversion circuithaving finders LC and CC arranged. toseize jacks LJ and CJ respectivelyinto which the operator can plug the double-cord '1 in the usualway,fthe plugsfof this cord being indicated by .R and A respective'ly.vV H 'With an" arrangement of this kind, the inethod of operation forcalling or answering o'ver'a l'st classfci'rcuitis the same for theoperator asthe ine'thod'ef operating over lower class circuits. "Inbe'th-cases, the operator plugs in by means other double-cordl. 'If' theconnection has tobe extendedto a second, third or fourth class circuit,box or his. 2 genia si i :Z-vkegqn:

'8 Claims. (01.119427) nectiorr, and the connection made the usualwayover thedouble-cord.

ll-i on the other hand, tw'ol'st class circuits I steadof to ground.This substitution causes the pulling up of relay H3 of the callingcircuit ifig'. 2), a relay that only operates for a very strong currentobtained by ,the connection in series of the positive batteryand the negative battery, This relay-I 8 causes Irelay '22 (Fig. 4) to pull upinthe circuit:-battery, -operating contact of [8, wire 3 (Fig. 2),,grounded winding of relay 22 When relay 2 2 operates, relays 23 and :24,operate and-causethe pulling up of relays v25 of all the idlecircuits inthe circuit: ground on the wind-ingwof 26, -coperating contact of 24,and in multiple, jack 21, rest contact of relay 28, rest contact ;of:29, normal contact ef-f nder CC, windin of -rcl vrya .7 OTdGlQqll'JOprevent --a=circuit, whose amplifier tube L does not operate, frombecoming connected Lilo-the calling circuit, the following arrangementispiprovided according to vanother feature of the invention. v H

Upon operating, relayifica-uses the pulling up of; -relay :39 that:feeds amplif er tube L withheating-cur-rent. Furthermore, the operationof relay 25 connects- :gridtransformer; 31 of this tube to the source-10f potential; .-e. ;,-g-.-=of 400 C. PLQS.

ylff then tube Liopera-tes normally, relay '32 pulls up and actuatesrelay 33 over an operating cont act-of;;relay; 2'5; Relay; 33 connectsrelay 3- -to wiper 1c of-finden-LC across a rest contact of 2 8, andalso connects the electromagnetic clutch of this ;fi-nder:to,2therest-contact of relay 34. The ro ti oi finde -LC ta es p a e un 1 79trol of relay 34, which becomes actuated upon meeting -the ,-potentialapplied by operating irelay I18 (EigJZl tofthe-l'corresponding wire4,and stops the finder. Relay 34, upon becoming actuated lprevents thedouble test in the known mannenand-relays- 35i and 9 become energized inedea l V "c Whenfinder-LCihas stopped at the calling ist classcircuit,thecsetting-oi f nder CC of the diversion-circuit-to the called -lstclass circuit -is--ef fected as follows, under the control of relays- 3gnd--3 a l 4 =Be evl 2. is on e t d tow e z to lb ached over the circuit:relay 32, the anode and grid of amplifier tube L, and grid transformer3|, operating contact of relay 31, wiper and contact 1' of LC, wire 2,sleeve of jack LJ of the calling 1st class circuit (Fig. 2) wire ofanswering plug R (Fig. 3), condenser, wire 5 of calling plug A, sleeveof jack CJ of the called 1st class circuit (Figs. 1 and 2), contact l offinder CC (Fig. 4) 31 front 25 front and back to transformer 3|.

Furthermore, the operation of relay 31 causes the rotation of finder CCunder the control of the rest contact of relay 36. The finder rotateswith a 400 C. P. S. potential applied to its contact 1 I over anoperating contact of relay 31.

When finder CC is connected to contact 71 to which relay 32 isconnected, this relay becomes actuated. In order to prevent finder CCfrom being stopped at a wrong position by the operation of this relay,which might occur upon passage of finder CC to the positioncorresponding tothe calling 1st class circuit as well as to the positioncorresponding to the called 1st class circuit, the circuit is arrangedin such a Way that the pulling up of relay 32 is not sufficient to stopthe'hunting. Relay 32 connects relay 36 into the circuit of contact kl,and relay 36 becomes energized with the potential furnished by wire 6 ofFigs. 2 and 4 on condition that contact kl is not the one correspondingto the calling circuit because, at that position, a ground is connectedthrough the intermediary of operating relay 31 and wiper e of finder LC.

Upon operating, relay 36 shops the rotation of finder CC and effects thepulling up of relay 38.

According to another feature of the invention, finder CC starts from anormal position instead of startin from any position in order to preventthe possible occurrence of a wrong connection if two simultaneoushuntings took place and finder CC of connection No. 1 should meet relay32 of connection No. 2 at the moment when finder CC of connection No. 2met wiper k of connection No. 1.

Upon becoming actuated, relay 38 effects the release of relay 31, whichstops the operation of the amplifier tube and connects relays l8 and [9(Fig. 4) to contact ii of the called circuit.

During the establishment of the connection, the monitoring key-39 (Fig.3) of the two-cord is pressed down, and the connection remains a 2- wireone over this two-cord.

When the operator lifts her monitoring key, relay IQ of Fig. 3 connectsa low resistance ground over a rest contact of monitoring relay 40 towire 5 of calling plug A, and this causes the pullin up of relay IQ ofthe called circuit (Fig. 2).

Relay IS in its turn causes the pulling up of relay 4|, which cuts outattenuator 42 and connects a ground to wire 1 in series with relay 43.This relay becomes actuated in series with relays l8 and IQ of Fig. 4over an operating contact of relay 38.

Relay l9 (Fig. 4) causes the pulling up of relay 44 (Fig. 2) of thecalling circuit over wiper U and wire 8.

Relay 44 effects the pulling up of relay 4| of the calling circuit,which cuts out the attenuator 42 of this circuit and gives a signal tothe terminal box T to pass into 4-wire connection; terminal box T of thecalled circuit passes into 4- wire connection through the intermediaryof relay 43 and wire IT.

The conversation takes place over contact banks 1:, w, x, 11, vi, wl,ml, pl, of finders LC and CC, and the two-cord remains branched on thetwo talking channels in order to permit any necessary supervisionthrough the intermediary of key 45 which transfers the talking channelsto wires l3 to [6 respectively where the monitoring can be done throughan amplifier, if necessary.

If the monitoring key 39 (Fig. 3) is pushed down without theintermediary of key 45, the low resistance ground is removed from thewire 5 of calling plug A, relay [9 (Fig. 2) of the called circuitreleases, cancelling the operation of relays l8, 19, etc. (Fig. 4) asalready described, and the call again becomes a 2-wire one over thetwocord without the 4-wire link circuit being released.

Upon withdrawal of the plug of one of the ends of the two-cord, relay l8(Fig. 2) of the calling circuit falls back and releases the 4-wire linkcircuit of Fig. 4. A new call can be handled.

Although the invention has been described for one particular example ofembodiment, it is evident that it is by no means limited to the same,but on the contrary is capable of numerous modifications and adaptationswithout departing from its scope.

What is claimed is:

l. A telephone exchange system comprising a plurality of lines includinga calling line and a called line, a cord circuit connecting the callingand called lines, a plurality of switches each having a plurality ofterminals multipled to said lines and a plurality of brushes, a switchdriving system, means actuated by the connection of the cord circuitbetween the calling and called circuits for actuating the drivingsystem, a plurality of supplemental circuits each connected at each endto the brushes of a difierent switch and means for arresting theswitches when a switch connected to a supplemental circuit contacts thecalling line.

2. A telephone exchange system comprising a plurality of lines includinga calling line and a called line, a cord circuit connecting the callingand called lines, a plurality of hunting switches each having aplurality of terminals multipled to said plurality of lines and aplurality of brushes, a plurality of supplemental circuits eachconnected at each end to brushes of a difierent switch, first meansactuated by a circuit extending through the cord circuit for drivin idleswitches until a switch connected to one end of a supplemental circuitcontacts the calling line and thereupon arresting the switches, andsecond means for thereupon shifting the switch at the other end of thelatter supplemental circuit into contact with the called line.

3. A system as set forth in claim 2 in which each line includes anattenutating arrangement and means for cutting out said attenuatingarrangement when the line is connected to another line through the cordcircuit and a supplemental circuit.

4. A system as set forth in claim 2 in which the supplemental circuitincludes an attentuatlng arrangement, and means for connecting saidattenuating arrangement between the calling and called lines after thesupplemental circuit has been connected to the latter lines.

5. A telephone exchange system comprising a plurality of lines includinga calling line and a called line, a cord circuit connecting the callingand called lines, a plurality of hunting switches each having terminalsmultipled to said plurality of lines and a plurality of brushes, aplurality of supplemental circuits each connected at each end to brushesof a difierent switch, and means for actuating said switches to connecta supplemental circuit to the calling and called lines including aswitch driving arrangement and an actuating circuit therefor extendingthrough the cord circuit and energized through connections to both thecalling and the called line.

6. A system as set forth in claim 5 in which the actuating circuitincludes two relays, an energizing circuit for one relay connected tothe calling line and an energizing circuit for the second relayconnected to the called line, said actuating circuit extending throughnormally open contacts of both of said relays.

7. A system as set forth in claim 5 in which each supplemental circuitincludes a vacuum tube and the means for actuating the switches includescircuits passing through said tube, arranged to prevent operation ofswitches connected to a supplemental circuit which includes a defectivetube.

8. A system as set forth in claim 5 in which the switch driving meansincludes an actuating circuit in the supplemental circuit, means forclosing the latter circuit when the connections to the calling line arecompleted, and means for opening the latter circuit including a circuitextending from the connected supplemental circuit through the callingline, cord circuit and called line to the switch terminals and from saidconnected supplemental circuit to a brush of the driven switch connectedto the latter circuit.

ANDRE JEAN HENQUET.

MARCEL ROGER MAUGE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,647,796 Glezen Nov. 1, 19271,708,982 Vroom Apr. 16, 1929 1,763,893 Krecek June 17, 1930 2,265,151Crocker Dec. 9, 1941

